Improvement in compounds for bating hides and skins



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CHARLES F. PANKNIN, OF CHARLESTON, SOUTH CAROLINA.

LettersPatent No. 109,656, dated November 29,1870 antedated November 26, 1870.

IMPROIVEMENT m COMPOUNDS FOR BATlNG HIDES AND SKINS.

I The Schedule referred to in these Letters Patent and making part-of the same.

To all whom it may concern:

Be it known that I, CHARLES 1 PANKNIN, of the city and county of Charleston, in the State of South Garolina, have invented a new and improved Liquid or Solution for Eating Hides and Skins; and I do herebydeclare that the following is a full, clear, and exact description of the manner of compounding and using the same. e

I employ a solution composed of, say threefourths (3) of a pound of carbolic acid, six (6) pounds of-muriate of ammonia, (sal ammoniac,) and six (6) pounds of alum, dissolved in one hundred and fifty gallons of water.

lhese proportions may be varied without departing from the principle of my invention. I

I explain the action of this hate on hides 'or skins which have been depilated by lime as follows:

The lime remaining in the skin or hide after all mechanical means have been employed (such as repeated washing, rinsing, scraping, and soaking, &c.,) for its removal, does not amount to a large percentage, still there is suflicient lime left to form, with the tannin an insoluble compound, which retards the progress of tanning by closing the pores and preventing the tan liquid 'from penetrating the interior of the hides or skins, asidefi'rom which 'leather containing this tannate of limeis often harsh and brittle.

When hides or skins are immersedin this liquid (after being freed from the lime by mechanical means) for twenty-four hours or longer, all the remaining lime is entirely removed, and the pores of the hides or skins I lime, when brought into contact with the solution above named, produce a chemical reaction. The muriate of ammonia-is decomposed in the presence of lime, forming chloride of calcium, which is soluble in water, and ammoniais liberated, which unites with a portion of the sulphuric acid contained in the alum,

forming sulphate of ammonia and alumina. if alum were not present the ammonia would give to the bate an alkaline reaction, which would be unfavorable to a proper swellin The reaction of this bate is, however, uniformly acid, without containingany free acid.

The advantages ofthe carbolic acid in the bate are to prevent any tendency to 'putrefaction or fermentation, and at the same time beginthe operation of ten ning by coagulating and loosening the albumen from the elastic fiber, and it also'makes the fibers tougher.

Another advantage in the use of carbolic acid is the prevention of an undue swelling of the 'fihers, which would injuriously affect the quality of the leather produced. a

The general advantages of the improved bate are:

First, the economy in the cost of material.

Second, the swelling of the hides and skins, and the removal of the lime at the same time.

-Third, the more rapid tanning of the hides and skins. 1 p

Fourth, the fibers of the hides and skins are not impaired by any free acid.

Filth, hides and skinswhioh have been treated with my bate, after they have been colored in the vat with a weak tan liquor, will bear a stronger tan solution z'rfterward without detriment.

Sixth, the leather produced is much more pliable, tougher, and plumped up.

Seventh, the catholic acid retained by the hides and skins will cause a saving of tannin in the vats, as it has the property of retarding the conversion of tannin into gallic acid. f

When the hides and skins have. been depilated with out the use of lime, I prefer to employ the solution without the muriate of ammonia, or with only a. very small quantity of ,muriate of ammonia, as this salt is only added for the removal of the lime.

'ihc hides and skins should be worked in the improved bate precisely as in any other. And in regard to the length of time each hide or skin is to re-. main in the hate, this will dependon the thickness and other conditions of .the same. Practical tannerswill know when the hides are bated sufficiently; and

'in order to make the hate penetrate uniformly they specified.

CHARLES- F. PANKNIN. Witnesses G. W. Drnemg,

0. W. STILns. 

